1. Field of the Invention
This invention relates generally to packet telephony communications, and, more particularly, to methodologies and concomitant circuitry for applying active networking to existing call signaling, call setup, and mobility management.
2. Description of the Background
The Internet is expected to see continued growth in supporting personal and commercial services. Currently IP telephony provides voice service to end terminals that are attached to wired networks. With the proliferation of mobile and wireless services and as more users disconnect from their fixed access points and become mobile, there is an increasing need to adapt Voice-over-Internet Protocol (VoIP) to the wireless domain.
However, the wireless environment is dynamic in nature due to the mobility of the end terminals and the variability of the over-the-air channel. Moreover, the mobile wireless environment is much more dynamic than the traditional wireline environment. The uncertainties of the wireless and mobile environments call for an increased level of adaptability. For more robust real-time communications, a signaling protocol is vital in providing highly reliable and robust connectivity in such a communications environment. In addition to establishing and releasing a call, a signaling protocol must also monitor and maintain connectivity when the end-terminal is moving and/or the transmission capabilities are varying. Successful installation of VoIP across network elements with differing capabilities and over a dynamic wireless channel requires signaling protocols to have flexible and self-adaptive functionality.
Moreover, besides signaling, it is necessary to provide for the xe2x80x9cmobilityxe2x80x9d of a wireless terminal as it moves from one serving cell to another serving cell during an established call. Finally, in order to provide complete service to the wireless terminal, it is necessary to further combine the operations fostered by signaling and mobility so as to ensure setup and connectivity of a wireless terminal as it moves from one serving cell to another during a call setup.
Active networks are a class of networks that can be leveraged to provide this adaptability. An active network allows intermediate nodes to perform computations specified by packets or modify in-transit packets. This technique allows programs to be executed or structures to be reconfigured in the network based on programs and/or data contained in the packets traversing the network. Thus, this technique injects a degree of intelligence and flexibility into current network elements that can be configured and programmed to suit a variety of needs. Moreover, this type of processing can be customized on a per-user or per-application basis.
A recent disclosure relating to active networks is the subject matter of U.S. Pat. No. 5,949,780 issued to Gopinath. The subject matter of this patent relates to methodologies and concomitant circuitry for coalescing intelligence with communications in a switching node. The inventive aspects of ""780 suggestions related to program execution in the switch based upon the following actions/events (an event triggers an action which, in turn, generates a desired response): the state of the program itself, the state of resources composing the switch; external control inputs serving the switch; other programs executing in the switch; data (packets) received over other ports of the switch; or combinations of these actions/events. In addition, the inventive aspects covered an implementation in conjunction with a switch wherein a new program may be downloaded to the switch, and then this new program may be executed, together with other stored programs if necessary, based upon data incoming to a port as well as any or all the foregoing actions/events.
In accordance with the broad method aspect of ""780, a communications service is implemented with a program stored in a processing unit having input and output ports to receive and transmit messagesxe2x80x94each message is composed of canonically, a control tag and payload information. For each port, data is retrieved and then parsed by the program to determine if the control tag and/or the payload information are to be modified. Based upon the parsing, the incoming message can be sent to one or more other ports, or further processed by the program or other stored programs to produce desired actions.
As alluded to above, mobility management is important in the wireless environment, and currently mobility in the Internet is supported by the Mobile IP protocol. Mobile IP identifies a mobile node (e.g., a mobile terminal) by its permanent home address, regardless of its current point of attachment in the Internet. While away from its home network, the mobile node acquires a xe2x80x9ccare-of addressxe2x80x9d that reflects its current point of attachment. By default, Mobile IP uses an agent in the home network to redirect (by encapsulation) packets destined for the home address to the care-of address. This redirection causes Mobile IP to be inefficient (triangular routing) and not robust (relies on a home agent and sometimes on a foreign agent). Mobility support in IPv6 has moved in the direction of end-to-end location updates using the facilities of IPv6 to send binding updates. In addition to sending its binding to its home agent, a mobile terminal can send the binding to the corresponding node communicating with it. When sending a packet, the corresponding node checks it""s binding for the destination address. The packet is then sent directly to the care-of address without going through the home agent if the binding is found. This improves routing efficiency. However, it still requires communications via the home agent when the corresponding node does not know the current location of the mobile, or when both nodes can be mobile simultaneously, or if the mobile wants to hide its location.
The prior art is devoid of teachings or suggestions relating to: generating an active packet in a mobile terminal to provide information for instantiating an agent in the fixed network to handle signaling between the mobile terminal and the fixed network, and then instantiating the agent in the fixed network to negotiate setup of an open channel between the mobile terminal and the destination device. The instantiation of the agent mitigates use of bandwidth between the mobile terminal and the fixed network.
Moreover, the art is devoid of teachings or suggestions relating to generating an active packet to foster the handoff of a mobile terminal as the terminal moves from one cell to another in a subnet.
Finally, there are no teachings or suggestions in the art relating to ensuring completion of the signaling operation as a mobile terminal is handed off from one cell to another in a subnet.
Shortcomings and limitations of the prior art are obviated, in accordance with the present invention, by a methodology and concomitant circuitry wherein, generally, an active packet transmitted from a mobile terminal initiates execution of a mobility process in the communications network to handle handoff of the mobile terminal as it moves within a subnet.
Broadly, in accordance with one method aspect of the present invention, a method for managing the mobility of a wireless mobile terminal in a subnet of a network, the subnet being served by a plurality of base stations, includes:
(a) transmitting an active packet from the terminal to one of the base stations; and
(b) executing a mobility process in the base stations of the subnet in response to the active packet being received by said one of the base stations.